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Biomedical subjects

S Hayasaka

Publications and source records attributed to S Hayasaka.

At least 307 records · Page 17Linked to original sources
PubMed1978

The distribution and some properties of collagenolytic cathepsin in the bovine eye.

In vitro degradation of insoluble vitreous collagen by the action of collagenolytic cathepsin was studied biochemically. Among bovine ocular tissues, the uvea and the retina showed relatively high collagenolytic activity. The ciliary body revealed the highest specific activities of both cathepsin B and collagenolytic cathepsin. Leupeptin and p-chloromercuribenzoate inhibited both cathepsin B and collagenolytic cathepsin in the ciliary body lysosomes. Pepstatin inhibited cathepsin D, but did not affect cathepsin B and collagenolytic cathepsin. It is suggested that distribution and properties of collagenolytic cathepsin are similar to those of cathepsin B in the bovine eye.

Animals↗
PubMed1978

The presence of collagenolytic cathepsin in uveal lysosomes of bovine eye.

Collagenolytic cathepsin, which can liberate soluble hydroxyproline-containing products from insoluble vitreous collagen with maximum activity at pH 3.5, was biochemically studied in uveal lysosomes of bovine eye. Collagen solubilization was proportional to both enzyme concentration and incubation time. When the enzyme was heated, no reaction was observed. Collagen solubilization by uveal lysosomal extract was almost unaffected by Ca2+ ion, cysteine, beta-mercaptoethanol, and ethylenediaminetetraacetic acid, but inhibited about one-third by pepstatin. The possible role of collagenolytic cathepsin in vitreous liquefaction was considered.

Animals↗
PubMed1978

Effects of epinephrine, indomethacin, acetylsalicyclic acid, dexamethasone, and cyclic AMP on the in vitro activity of lysosomal hyaluronidase from the rabbit iris.

The effects of epinephrine, indomethacin, acetylsalicylic acid, dexamethasone, and cyclic AMP on lysosomal hyaluronidase activity in in the rabbit iris were studied in vitro. Indomethacin and acetylsalicylic acid inhibited the lysosomal hyaluronidase activity. Dexamethasone and cyclic AMP (adenosine-3',5'-cyclic monophosphate) had little effect on the enzyme activity. Epinephrine activated the enzyme activity. These drugs had no effect on the activities of either bovine testicular hyaluronidase or rabbit iridial acid phosphatase. The possible role of lysosomal hyaluronidase in the rabbit eye and the drug effects were considered.

Acid Phosphatase↗
PubMed1978

The presence of lysosomal hyaluronidase in the rabbit iris.

Lysosomal hyaluronidase in the rabbit iris was studied by means of a sensitive assay method based on carbocyanine dye binding. The enzyme activity in the lysosomal extract was proportional to both the enzyme concentration and the incubation time. When the enzyme was heated, the enzyme activity was lost completely. When the lysosomal extract was used as an enzyme source, the enzyme activity was protected by pepstatin. The enzyme had a pH optimum of 3.8 and no activity above pH 5.0.

Animals↗
PubMed1978

Distribution of acid phosphatase, beta-glucuronidase, and lysosomal hyaluronidase in the anterior segment of the rabbit eye.

Distribution of acid phosphatase, beta-glucuronidase, and lysosomal hyaluronidase in the anterior segment of the rabbit eye was studied biochemically. Acid phosphatase activity was higher in the anterior uvea and cornea but lower in the sclera. Beta-Glucuronidase activity was higher in the anterior uvea but lower in the corneoscleral tissues. Lysosomal hyaluronidase activity was higher in the anterior uvea. The inner layer of the corneoscleral junction showed the highest specific activity of beta-glucuronidase and lysosomal hyaluronidase among the corneoscleral tissues. Lysosomal hyaluronidase activity was detected in all corneoscleral tissues.

Absorption↗
PubMed1977

Lysosomal enzymes in the serum of patients with with Behçet's disease.

Samples of serum from patients with ocular manifestation of Behçet's disease of various types were analyzed using acid phosphatase and beta-glucuronidase as lysosomal marker enzymes, in comparison to those from control patients with myopia, retinal detachment, and uveitis of unknown etiology. The lysosomal enzyme activities in Behçet's disease, especially in the attack phase, were found to be higher than those of the controls. In the sera of two patients with Behçet's disease, the activities in the attack phase were slightly higher than in the remission phase. It was suggested that the ocular symptoms in Behçet's disease might represent exacerbation better than other symptoms, in view of the high lysosomal enzyme activities in the attack phase, as classified by ocular symptoms alone.

Acid Phosphatase↗
PubMed1976

Lysosomal enzymes in subretinal fluid.

Samples of subretinal fluid (SRF) from patients with primary rhegmatogeneous retinal detachment of various duration were studied using standard enzymologic techniques. The protein content in SRF increased with the duration of detachment. The activities of lysosomal enzymes in SRF, which were acid phosphatase, beta-glucuronidase, and cathepsin D, also increased with the duration of detachment. Especially cathepsin D, which was not detected in serum, was present in SRF. The activity of a nonlysosomal enzyme, i. e., lactic dehydrogenase, which was used as a marker of cell disruption and of serum transudation was the same as that of serum. Because lysosomal enzymes are known to be able to degrade cells and tissues, the enzymologic analysis of SRF contributes to our understanding of the pathology of primary rhegmatogeneous retinal detachment.

Acid Phosphatase↗
PubMed1975

Degradation of rod outer segment proteins by cathepsin D.

The degradation of proteins of the rod outer segment (ROS) fraction by partially purified cathepsin D [EC 3.4.23.5] from the retinal pigment epithelium was studied. The ROS fraction, prepared from bovine eyes by sucrose density gradient centrifugation, had little cathepsin D activity. Partially purified cathepsin D, obtained from crude extract of bovine retinal pigment epithelium using bovine serum albumin as a substrate, hydrolyzed the porteine of the ROS fraction. The rate of degradation of ROS proteins was proportional to both the enzyme concentration and the incubation time. With ROS proteins as substrate, the optimal pH of cathepsin D was about 3.5. The degradation of ROS proteins was inhibited by pepstatin.

Animals↗
PubMed1975

Partial purification and properties of cathepsin D in the retinal pigment epithelium.

Cathespin D from the retinal pigment epithelium of bovine eyes was purified about 25-fold from a crude extract of retinal pigment epithelium by acid treatment, ammonium sulfate fractionation, and Sephadex G-200 column chromatography. The purified enzyme hydrolyzed bovine serum albumin optimally at pH values close to 4.0. Exposure of the enzyme to 60 degrees C. for 2 minutes resulted in 50 per cent inactivation of the activity. The enzyme activity was completely inhibited by 0.1 microgram per milliliter of pepstatin, slightly inhibited by trasylol, and not affected by soybean trypsin inhibitor. The apparent molecular weight of cathepsin D was estimated to be about 60,000 by gel filtration on Sephadex G-200.

Animals↗